Analysis of the Rollover Behavior of the Bus Bodies (original) (raw)
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About the Study of the Bus Structure Behavior in Case of Rollover, Using Numerical Simulation
The objective of this paper is the highlighting of the main aspects that be considered in study of the bus structure behavior in case of roll-over, using numerical simulation of this real situation. In first part of the paper are presented, briefly, the general framework and the reference documents governing the mechanical protection of the passengers in case of the bus rollover. Next, the main parameters defining the numerical simulation of rollover bus are analyzed. Also is analyzed the influence of these parameters on the accuracy of the numerical results obtained by simulation. In this context, are given the necessary information to correctly modeling the reality so that the results to have an imposed accuracy.
Rollover Analysis of Passenger Bus as per AIS-031
2012
Road transport is the most commonly used way of transportation in India and in many countries. The passenger bus plays an important role in public transport. The capacity of carrying more passengers compared to other road transport medium is unfavourable in the event of major bus accident. The rollover crash accident of passenger bus, although occurs less frequently than any other type of accident, the fatality rate and severe injuries are highest in rollover crash. Hence the structure of the bus needs to be strong enough to ensure the minimum damage and at the same time it should absorb maximum impact energy. Safety regulations are in force defining minimum structural rigidity under rollover crash. The Automotive Industry Standard (AIS-031) is implemented in India since October 2008 which specifies the requirements and methods to calculate the strength of superstructure of buses during and after rollover. The AIS-031 specifies four different test methods viz. physical rollover test on a complete vehicle, rollover test on a body section, pendulum test on a body section, and verification of strength of superstructure by calculation (numerical simulation). In this work numerical simulation of rollover test using finite element method is followed. First the numerical model is build according to the guidelines provided in AIS-031 and validated by the experimental testing. A validated numerical model is used to evaluate the rollover performance of the superstructure of the bus.
Rollover Analysis of Bus Body Structure as Per AIS 031/ECE R66
Bus rollover is one of the most serious types of accident as compared to other modes of bus accidents. Strengthening bus frames to maintain residual space (occupant space) and minimizing occupant injury are necessary. This paper deals with the study of bus roll over case as per AIS 031/ECE R66 regulation conditions. The AIS 031 is equivalent to ECE R66 regulation but excluding for driver and co-driver. The ultimate aim of this study was to investigate the impact on passenger residual space as per AIS 031 regulation. As a first step, before we go for complete rollover simulation, the critical bus body joints are physically tested same is repeated by simulation approach once we have the correlating results approval is taken from ARAI. As a second step, the complete vehicle rolls over simulation was performed. FE model of the full vehicle was comprised of first order shell elements, spring elements, mass elements (ADMAS) and Rigid Elements. An average Element edge length of 10 mm is maintained in the critical regions and 30 mm in the noncritical regions. The engine, power transmission, suspension and axles were modeled by 1D element. Mass balancing was done using balancing tool in HyperCrash V11 402. Computer simulation of the joint test was showing low load carrying capacity of joints as compare to test results which means computer simulation was showing higher deformation (lower distance b/w superstructure & residual space) as compare to physical testing. Hence simulation results are conservative compared to test, if bus passes in simulation then we have confidence that it will pass in test with more margin. During roll-over simulation, the minimum distance between superstructure & residual space was found to be 38.0 mm on driver side as per AIS-031. The Volvo Bus was found to meet the Rollover requirement as per AIS-031. FE modeling & model setup of the entire bus structure was carried out using HyperMesh and HyperCrash respectively. Finally, simulation was carried out using RADIOSS explicit solver. Unit system followed: KN, mm, ms, kg
Experimental Test and Computer Simulation Research on Rollover Impact of a Bus Structure
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Bus structures are tested to ensure that no element enters the survival space during an rollover impact. In this paper an experimental of rollover test using body sections as an equivalent approval method is presented. The mass of the structure is bigger than the maximum acceptable one. Therefore, some elements of the structure enter the survival space for a little time during the impact, but in the last moments of the impact they are out of the survival space. The intrusion could be seen only using a video camera. These deformations were supposed to be obtained using a virtual simulation. Simulation results were very close to the experimental ones, but for the best fitting more parameters had to be modified. The deformation obtained using two different simulation models are compared with the experimental one. Key-Words: bus structure body sections Ansys rollover simulation
Quasi-static simulation approaches on rollover impact of a bus structure
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The dynamic simulations of rollover behaviour of bus bodies require more computation time than the quasi-static simulations. This paper presents a study of several different virtual simulations of quasi-static loading test on body sections as an equivalent approval method of UNECE Regulation Number 66. The body section is analyzed by using the Transient Structural and Static Structural modules of Ansys. The scenarios analyze some new methods of deforming a structure by applying a force or a displacement to a plate which is in contact with a frame of the roof, or by applying different angle displacements directly to the frame. Resulting deformations are compared with a physical reference model, the absorbed energy is analyzed and a necessary mass of the structure is computed for each of the models. In some models the deformation is similar to the reference structure. Key-Words: quasi-static, rollover, bus, structure, Ansys, simulation, body section, residual space
Finite Element Analysis of Bus Rollover Test in Accordance with UN ECE R66 Standard
Journal of Engineering and Technological Sciences, 2017
Bus transportation plays a significant role in short and long distance mass transportation in Indonesia. The number of buses in Indonesia shows significant growth every year. However, there is a lack of regulations regarding bus construction safety and the increasing number of bus accidents is also becoming a major concern. In this paper, a computer simulation of bus rollover is presented. The bus structure was modeled to represent the mass distribution in a real bus. Two conditions were tested: the bus when empty and when fully loaded. Both the empty bus and fully loaded bus simulation results show that the bus did not comply with the UN ECE R66 safety standard. The results were validated by making a comparison with other tests that have been conducted by other researchers.
Experimental Research of the Behavior of a Bus Structure in Case of Rollover
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Public transport or public transit is a term that means a shared passenger transport service which is available for use by the general public, as distinct from modes such as taxicab, car pooling or hired buses which are not shared by strangers without private arrangement. Public transport modes include buses, trolleybuses, trams and trains, rapid transit (metro/subways/undergrounds etc) and ferries. Public transport between cities is dominated by airlines, coaches, and intercity rail. High-speed rail networks are being developed in many parts of the world. Below are presented the main advantages of public transport compared to private transport, and some comments on them. Reducing air pollutant emissions and fossil fuel consumption. In this context, the using of the public transport can result in a reduction of an individual’s carbon footprint. A single person, 35 km-round trip by car (e.g. home to work and work to home) can be replaced using public transportation and result in a ne...
Investigating the rollover propensity of a 15 seater mini bus
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In the present paper a full vehicle model of the Rural Transport Vehicle (RTV) is developed in MADYMO. The steering, tyre and suspension are modelled using standard modules available in the package. A speed controller was also designed using the package to maintain a constant speed of the RTV in simulations. Validation of the model was against experimental accelerations measured over bumps. The validated model is used to predict rollover characteristics using Slowly Increasing Steer (SIS), J-turn and Road Edge Recovery (RER) manoeuvres. These manoeuvres were conducted for three different loading conditions viz. RTV without passengers, RTV with unrestrained passengers and RTV with restrained passengers.
American Journal of Engineering and Applied Sciences
Dynamics, or dynamic processes, is the part of mechanics dealing with the study of processes trying to describe as real as possible the movement of a body, element, mechanism, car, etc., also taking into account the action of the forces on the respective system with their influence on the actual movement of system. The present paper aims to present the study of the dynamics of the vehicles, with particularization on the buses. Here are the main elements of the bus dynamics, taking into account all the elements that influence the dynamic operation of a bus, in general and in particular situations, with emphasis on the main systems and elements that act on the actual, dynamic, on a normal path or on an inclined with an alpha angle path. The position of the bus center on a bus needs to be known first in order to study the stability of the bus and then to determine the normal dynamic reactions for the suspension design... The position of the center of mass in the longitudinal plane is determined by weighing the bus on a tiller. In the beginning determine the maximum total mass of the G t bus and then two other weights determine the loads G 1 and G 2 that belong to the front and to the rear axle. The stability of the bus will be studied, which means its ability not to overturn or slip during travel or in stationary. The longitudinal stability of the bus means its ability not to overturn around the rear or front wheels or to slip longitudinally when climbing a slope. Figure 3 considers a bus that climbs a slope at a low and uniform speed. The movement can be considered because the overturning can occur in the case of large slopes. Flipping around the straight line through the contact points B of the rear wheels with the road may occur when the tipping moment is greater than the moment of stability relative to the same point, i.e.
A roll-over event is one of the most crucial hazards for the safety of passengers and the crew riding in a bus. In the past years it was observed after the accidents that the deforming body structure seriously threatens the lives of the passengers, thus the roll-over strength has become an important issue for bus and coach manufacturers. Today the European regulation "ECE-R66" is in force to prevent catastrophic consequences of such roll-over accidents thereby ensuring the safety of bus and coach passengers. According to the said regulation the certification can be gained either by full-scale vehicle testing, or by calculation techniques based on advanced numerical methods(i.e. non-linear explicit dynamic finite element analysis). The quantity of interest at the end is the bending deformation enabling engineers to investigate whether there is any intrusion in the passenger survival space(residual space) along the entire vehicle.